Investigators picked through debris across a fire-blackened soybean field Tuesday to try to determine why a U.S. military plane slammed into the ground, killing all 16 people aboard in the deadliest Marine crash anywhere in the world in more than a decade.

A retired marine living just miles away — passed the scene Monday but came back the next morning to pay his respect to the 16 fallen heroes:

“First thing I did was drop down on my knees and prayed,” he said. “I mean, that’s the best I can do try to honor their memory by coming out here and paying my respects to them.”